Alejandro Celaya: Reusing factories in Zend ServiceManager

Alejandro Celaya has a new post to his site showing the Zend Framework users out there how you can reuse factories in Zend/ServiceManager. Factories are heavily utilized by the component to create the objects the service returns. Factories tend to be single-use, however, but Alejandro has shown a way around that.

I like zend-servicemanager because it is explicit, and you are always in control of what's done, without loosing flexibility in the process. Since this container expects you to define factories for every service, you usually end up writing, testing and maintaining a lot of factories that doesn't add value to the application.

That's why it is so important to properly reuse factories when possible, not only because you will have to maintain less classes, but because the ServiceManager will instantiate less objects at runtime when it can reuse a factory.

He then talks about ways you can set up shared factories in your application including the use of an abstract factory class or a concrete factory to return other dependencies required. He also shows how to use the ConfigAbstractFactory that allows for the injection of dependencies based on a configuration (similar to the "wiring" in other dependency injection containers). Finally he shows the use of the ReflectionBasedAbstractFactory that handles the injection in about the same way but instead of basing it on a configuration it uses PHP's own reflection to try to determine the class and autoload it into the current system.